Oil prices rose on Monday as fresh tensions in Yemen and Iraq raised concerns about a supply disruption in the crude-rich Middle East, analysts said.
US benchmark West Texas Intermediate for delivery in June gained 53 cents to $60.22 a barrel compared with Friday's close.
Brent North Sea crude for July climbed 20 cents to stand at $67.01 in London midday deals.
Saudi Arabia-led coalition air strikes resumed against rebel positions in Yemen's south after a five-day ceasefire expired late Sunday, as fighting raged between Shiite Huthi rebels and loyalists of exiled president Abedrabbo Mansour Hadi.
And in Iriaq Islamic State fighters have seized the city of Ramadi in a deadly three-day blitz, with the effective loss of the capital of Iraq's largest province and becoming Baghdad's worst military setback since it started clawing back land from the jihadists late last year.
Vandana Hari, editorial director at global commodity information provider Platts, said the oil market remains "volatile" due to geopolitical tensions in the Middle East.
"Traders are keeping a close eye on the situation in that region as it has an impact on global oil supply," said Hari.
Yemen is not a major oil-producing country, but its coast forms one side of the Bab el-Mandeb Strait, the key strategic entry point into the Red Sea through which some 4.7 million barrels of oil pass each day on ships headed to or from the Suez Canal.
Baghdad is almost entirely dependent on oil revenues and falling crude prices have hit it hard at a time when its expenditures have increased because of the battle against IS militants.
Analysts say however that any gains in oil prices are being capped by continued concerns over a global oversupply in the face of weaker demand.